Catalyst system for the polymerization of olefins

ABSTRACT

A solid catalyst component for the polymerization of olefins, comprising: an inert porous support, Mg, Ti, halogen and an electron donor selected from succinates of formula (I) wherein the radicals R 1  and R 2,  equal to or different form each other, are hydrocarbon groups, the radicals R 3 , R 4 , R 5  and R 6 , equal to or different from each other, are hydrogen or hydrocarbon groups.

The present invention relates to a catalyst component supported on aninert porous support for the polymerization of olefins, and to the useof said catalysts in the polymerization of olefins CH₂═CHR in which R ishydrogen or a hydrocarbyl radical with 1-12 carbon atoms. In particularthe present invention relates to a catalyst component, suitable for thestereospecific polymerization of olefins, comprising Ti, Mg, halogen andan electron donor compound selected from esters of succinic acids(succinates). Said catalyst component is supported on an inert poroussupport such as porous polymer or porous inorganic oxides. This catalystwhen used in the polymerization of olefins, and in particular ofpropylene, are capable to give polymers in high yields with highisotactic index expressed in terms of high xylene insolubility and broadmolecular weight distribution (polydispersity). The chemical class ofsuccinates is known in the art. EP-A-86473 mentions the use ofunsubstituted succinates as internal donors in catalyst components forthe polymerization of olefins. The use of diisobutyl succinate anddi-n-butyl succinate is also exemplified. The results obtained in termsof isotactic index and yields are however poor. The use ofpolycarboxylic acid esters, including succinates, as internal donors incatalyst components for the polymerization of olefins, is alsogenerically disclosed in EP 125911. Diethyl methylsuccinate and diallylethylsuccinate are mentioned in the description although they are notexemplified. Furthermore, EP263718 mentions, but does not exemplify theuse of diethyl methylsuccinate and di-n-butyl ethylsuccinate as internaldonors. Substituted succinates are cited in WO 00/63261 but in thisdocuments it is not cited the possibility to support the catalyst systemdescribed herein. Supported catalyst system containing Ti, Mg, halogenand a diether as internal donor are known from U.S. Pat. No. 5,122,432.It relates to a catalyst system containing Ti and Mg, and a diether asinternal donor supported on a metal oxides. According to this documentthe supported catalyst system is more active and more stereospecificthan the unsupported one. This document does not relates to a catalystsystem containing a succinate as internal donor. U.S. Pat. No. 5,244,855relates to a catalyst system containing Ti, Mg, and an electron donorcompounds supported on a porous organic resin. The described catalystsystem has an enhanced stereoselectivity and produces polymer with abetter morphology than the unsupported one. Even if succinates are citedas electron donor compounds, they have never been tested. The applicantfound that when a catalyst system comprising magnesium, a titaniumcompound and a succinate as electron donor is supported on an inertporous support it is possible to obtain polymers having a broadermolecular weight distribution (polydispersity) than the unsupportedcatalyst. An object of the present invention is a solid catalystcomponent for the polymerization of olefins CH₂═CHR, in which R ishydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising aninert porous support, Mg, Ti, halogen and an electron donor selectedfrom succinates of formula (I):

wherein the radicals R¹ and R², equal to or different from each other,are a linear or branched, saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀cycloalkyl, C₆-C₂₀ aryl, C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical,optionally containing heteroatoms belonging to groups 13-17 of thePeriodic Table of the Elements; the radicals R³, R⁴, R⁵ and R⁶, equal toor different from each other, are hydrogen or a linear or branched,saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀ cycloalkyl, C₆-C₂₀ aryl,C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical, optionally containingheteroatoms belonging to groups 13-17 of the Periodic Table of theElements; and the radicals R³, R⁴, R⁵ and R⁶ which are joined to thesame carbon atom can be linked together to form a C₃-C₈ ring. R¹ and R²are preferably a linear or branched, saturated or unsaturated C₁-C₈alkyl, C₃-C₈ cycloalkyl, C₆-C₈ aryl, C₇-C₈ alkylaryl or C₇-C₈ arylalkylradicals. Particularly preferred are the compounds in which R₊ and R²are selected from primary C₁-C₈ alkyl radicals and in particularbranched primary C₁-C₈ alkyl radicals. Examples of suitable R¹ and R²groups are methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl,2-ethylhexyl. Particularly preferred are ethyl, isobutyl, and neopentyl.One of the preferred groups of compounds described by the formula (I) isthat in which R³ to R⁵ are hydrogen and R⁶ is a branched C₃-C₁₀ alkyl,C₃-C₁₀ cycloalkyl, C₆-C₁₀ aryl, C₇-C₁₀ alkylaryl or C₇-C₁₀ arylalkyl.Particularly preferred are the compounds in which R⁶ is a branchedprimary C₃-C₁₀ alkyl group or a C₃-C₁₀ cycloalkyl group. Specificexamples of suitable monosubstituted succinate compounds are diethylsec-butylsuccinate, diethyl thexylsuccinate, diethylcyclopropylsuccinate, diethyl norbornylsuccinate,diethyl(10-)perhydronaphthylsuccinate, diethyl trimethylsilylsuccinate,diethyl methoxysuccinate, diethyl p-methoxyphenylsuccinate, diethylp-chlorophenylsuccinate diethyl phenylsuccinate, diethylcyclohexylsuccinate, diethyl benzylsuccinate, diethyl(cyclohexylmethyl)succinate, diethyl t-butylsuccinate, diethylisobutylsuccinate, diethyl isopropylsuccinate, diethylneopentylsuccinate, diethyl isopentylsuccinate,diethyl(1,1,1-trifluoro-2-propyl)succinate,diethyl(9-fluorenyl)succinate, diisobutyl phenylsuccinate, diisobutylsec-butylsuccinate, diisobutyl thexylsuccinate, diisobutylcyclopropylsuccinate, diisobutyl(2-norbornyl)succinate,diisobutyl(10-)perhydronaphthylsuccinate, diisobutyltrimethylsilylsuccinate, diisobutyl methoxysuccinate, diisobutylp-methoxyphenylsuccinate, diisobutyl p-chlorophenylsuccinate, diisobutylcyclohexylsuccinate, diisobutyl benzylsuccinate,diisobutyl(cyclohexylmethyl)succinate, diisobutyl t-butylsuccinate,diisobutyl isobutylsuccinate, diisobutyl isopropylsuccinate, diisobutylneopentylsuccinate, diisobutyl isopentylsuccinate,diisobutyl(1,1,1-trifluoro-2-propyl)succinate,diisobutyl(9-fluorenyl)succinate, dineopentyl sec-butylsuccinate,dineopentyl thexylsuccinate, dineopentyl cyclopropylsuccinate,dineopentyl(2-norbornyl)succinate,dineopentyl(10-)perhydronaphthylsuccinate, dineopentyltrimethylsilylsuccinate, dineopentyl methoxysuccinate, dineopentylp-methoxyphenylsuccinate, dineopentyl p-chlorophenylsuccinate,dineopentyl phenylsuccinate, dineopentyl cyclohexylsuccinate,dineopentyl benzylsuccinate, dineopentyl(cyclohexylmethyl)succinate,dineopentyl t-butylsuccinate, dineopentyl isobutylsuccinate, dineopentylisopropylsuccinate, dineopentyl neopentylsuccinate, dineopentylisopentylsuccinate, dineopentyl(1,1,1-trifluoro-2-propyl)succinate,dineopentyl(9-fluorenyl)succinate.

Another preferred group of compounds within those of formula (I) is thatin which at least two radicals from R³ to R⁶ are different from hydrogenand are selected from C₁-C₂₀ alkyl, C₃-C₂₀ cycloalkyl, C₆-C₂₀ aryl,C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical optionally containingheteroatoms. Particularly preferred are the compounds in which the tworadicals different from hydrogen are linked to the same carbon atom.Specific examples of suitable 2,2-disubstituted succinates are: diethyl2,2-dimethylsuccinate, diethyl 2-ethyl-2-methylsuccinate, diethyl2-benzyl-2-isopropylsuccinate, diethyl2-(cyclohexylmethyl)-2-isobutylsuccinate, diethyl2-cyclopentyl-2-n-propylsuccinate, diethyl 2,2-diisobutylsuccinate,diethyl 2-cyclohexyl-2-ethylsuccinate, diethyl2-isopropyl-2-methylsuccinate, diethyl 2,2-diisopropyl diethyl2-isobutyl-2-ethylsuccinate, diethyl2-(1,1,1-trifluoro-2-propyl)-2-methylsuccinate, diethyl2-isopentyl-2-isobutylsuccinate, diethyl 2-phenyl-2-n-butylsuccinate,diisobutyl 2,2-dimethylsuccinate, diisobutyl 2-ethyl-2-methylsuccinate,diisobutyl 2-benzyl-2-isopropylsuccinate, diisobutyl2-(cyclohexylmethyl)-2-isobutylsuccinate, diisobutyl2-cyclopentyl-2-n-propylsuccinate, diisobutyl 2,2-diisobutylsuccinate,diisobutyl 2-cyclohexyl-2-ethylsuccinate, diisobutyl2-isopropyl-2-methylsuccinate, diisobutyl 2-isobutyl-2-ethylsuccinate,diisobutyl 2-(1,1,1-trifluoro-2-propyl)-2-methylsuccinate, diisobutyl2-isopentyl-2-isobutylsuccinate, diisobutyl 2,2-diisopropylsuccinate,diisobutyl 2-phenyl-2-n-propylsuccinate, dineopentyl2,2-dimethylsuccinate, dineopentyl 2-ethyl-2-methylsuccinate,dineopentyl 2-benzyl-2-isopropylsuccinate, dineopentyl2-(cyclohexylmethyl)-2-isobutylsuccinate, dineopentyl2-cyclopentyl-2-n-propylsuccinate, dineopentyl 2,2-diisobutylsuccinate,dineopentyl 2-cyclohexyl-2-ethylsuccinate, dineopentyl2-isopropyl-2-methylsuccinate, dineopentyl 2-isobutyl-2-ethylsuccinate,dineopentyl 2-(1,1,1-trifluoro-2-propyl)-2-methylsuccinate, dineopentyl2,2-diisopropylsuccinate, dineopentyl 2-isopentyl-2-isobutylsuccinate,dineopentyl 2-phenyl-2-n-butylsuccinate.

Furthermore, also the compounds in which at least two radicals differentfrom hydrogen are linked to different carbon atoms, that is R³ and R⁵ orR⁴ and R⁶ are particularly preferred. Specific examples of suitablecompounds are: diethyl 2,3-bis(trimethylsilyl)succinate, diethyl2,2-sec-butyl-3-methylsuccinate, diethyl2-(3,3,3-trifluoropropyl)-3-methylsuccinate, diethyl2,3-bis(2-ethylbutyl)succinate, diethyl2,3-diethyl-2-isopropylsuccinate, diethyl2,3-diisopropyl-2-methylsuccinate, diethyl2,3-dicyclohexyl-2-methylsuccinate, diethyl 2,3-dibenzylsuccinate,diethyl 2,3-diisopropylsuccinate, diethyl2,3-bis(cyclohexylmethyl)succinate, diethyl 2,3-di-t-butylsuccinate,diethyl 2,3-diisobutylsuccinate, diethyl 2,3-dineopentylsuccinate,diethyl 2,3-diisopentylsuccinate, diethyl2,3-(1-trifluoromethyl-ethyl)succinate, diethyl2,3-(9-fluorenyl)succinate, diethyl 2-isopropyl-3-isobutylsuccinate,diethyl 2-t-butyl-3-isopropylsuccinate, diethyl2-isopropyl-3-cyclohexylsuccinate, diethyl2-isopentyl-3-cyclohexylsuccinate, diethyl2-cyclohexyl-3-cyclopentylsuccinate, diethyl2,2,3,3-tetramethylsuccinate, diethyl 2,2,3,3-tetraethylsuccinate,diethyl 2,2,3,3-tetrapropylsuccinate, diethyl2,3-diethyl-2,3-diisopropylsuccinate, diisobutyl2,3-bis(trimethylsilyl)succinate, diisobutyl2,2-sec-butyl-3-methylsuccinate, diisobutyl2-(3,3,3-trifluoropropyl)-3-methylsuccinate, diisobutyl2,3-bis(2-ethylbutyl)succinate, diisobutyl2,3-diethyl-2-isopropylsuccinate, diisobutyl2,3-diisopropyl-2-methylsuccinate, diisobutyl2,3-dicyclohexyl-2-methylsuccinate, diisobutyl 2,3-dibenzylsuccinate,diisobutyl 2,3-diisopropylsuccinate, diisobutyl2,3-bis(cyclohexylmethyl)succinate, diisobutyl 2,3-di-t-butylsuccinate,diisobutyl 2,3-diisobutylsuccinate, diisobutyl 2,3-dineopentylsuccinate,diisobutyl 2,3-diisopentylsuccinate, diisobutyl2,3-(1,1,1-trifluoro-2-propyl)succinate, diisobutyl2,3-n-propylsuccinate, diisobutyl 2,3-(9-fluorenyl)succinate, diisobutyl2-isopropyl-3-ibutylsuccinate, diisobutyl 2-terbutyl-3-ipropylsuccinate,diisobutyl 2-isopropyl-3-cyclohexylsuccinate, diisobutyl2-isopentyl-3-cyclohexylsuccinate, diisobutyl2-n-propyl-3-(cyclohexylmethyl)succinate, diisobutyl2-cyclohexyl-3-cyclopentylsuccinate, diisobutyl2,2,3,3-tetramethylsuccinate, diisobutyl 2,2,3,3-tetraethylsuccinate,diisobutyl 2,2,3,3-tetrapropylsuccinate, diisobutyl2,3-diethyl-2,3-diisopropylsuccinate, dineopentyl2,3-bis(trimethylsilyl)succinate, dineopentyl2,2-di-sec-butyl-3-methylsuccinate, dineopentyl2-(3,3,3-trifluoropropyl)-3-methylsuccinate, dineopentyl 2,3bis(2-ethylbutyl)succinate, dineopentyl2,3-diethyl-2-isopropylsuccinate, dineopentyl2,3-diisopropyl-2-methylsuccinate, dineopentyl2,3-dicyclohexyl-2-methylsuccinate, dineopentyl 2,3-dibenzylsuccinate,dineopentyl 2,3-diisopropylsuccinate, dineopentyl2,3-bis(cyclohexylmethyl)succinate, dineopentyl 2,3-di-t-butylsuccinate,dineopentyl 2,3-diisobutylsuccinate, dineopentyl2,3-dineopentylsuccinate, dineopentyl 2,3-diisopentylsuccinate,dineopentyl 2,3-(1,1,1-trifluoro-2-propyl)succinate, dineopentyl2,3-n-propylsuccinate, dineopentyl 2,3(9-fluorenyl)succinate,dineopentyl 2-isopropyl-3-isobutylsuccinate, dineopentyl2-t-butyl-3-isopropylsuccinate, dineopentyl2-isopropyl-3-cyclohexylsuccinate, dineopentyl2-isopentyl-3-cyclohexylsuccinate, dineopentyl2-n-propyl-3-(cyclohexylmethyl)succinate, dineopentyl2-cyclohexyl-3-cyclopentylsuccinate, dineopentyl2,2,3,3-tetramethylsuccinate, dineopentyl 2,2,3,3-tetraethylsuccinate,dineopentyl 2,2,3,3-tetrapropylsuccinate, dineopentyl2,3-diethyl-2,3-diisopropylsuccinate. As mentioned above the compoundsaccording to formula (I) in which two or four of the radicals R³ to R⁶which are joined to the same carbon atom are linked together to form aC₃-C₈ ring are also preferred. Specific examples of suitable compoundsare 1-(ethoxycarbonyl)-1-(ethoxyacetyl)-2,6-dimethylcyclohexane,1-(ethoxycarbonyl)-1-(ethoxyacetyl)-2,5-dimethylcyclopentane,1-(ethoxycarbonyl)-1-(ethoxyacetylmethyl)-2-methylcyclohexane,1-(ethoxycarbonyl)-1-(ethoxy(cyclohexyl)acetyl)cyclohexane. It is easilyderivable for the ones skilled in the art that all the above mentionedcompounds can be used either in form of pure stereoisomers or in theform of mixtures of enantiomers, or mixture of diastereoisomers andenantiomers. When a pure isomer is to be used it is normally isolatedusing the common techniques known in the art. In particular some of thesuccinates of the present invention can be used as a pure rac or mesoforms, or as mixtures thereof, respectively.

As explained above, the catalyst components of the invention comprise,in addition to the above electron donors, an inert porous support, Ti,Mg and halogen. In particular, the catalyst components comprise atitanium compound, having at least a Ti-halogen bond and the abovementioned electron donor compound, and a Mg halide which are supportedon said inert porous support. The magnesium halide is preferably MgCl₂in active form which is widely known from the patent literature as asupport for Ziegler-Natta catalysts. Patents U.S. Pat. No. 4,298,718 andU.S. Pat. No. 4,495,338 were the first to describe the use of thesecompounds in Ziegler-Natta catalysis. It is known from these patentsthat the magnesium dihalides in active form used as support incomponents of catalysts for the polymerization of olefins arecharacterized by X-ray spectra in which the most intense diffractionline that appears in the spectrum of the non-active halide is diminishedin intensity and is broadened to form a halo. The preferred titaniumcompounds used in the catalyst component of the present invention areTiCl₄ and TiCl₃; furthermore, also Ti-haloalcoholates of formulaTi(OR⁷))_(ny)X_(y), where n is the valence of titanium, X is halogen andy is a number between 1 and n and R⁷ is a C₂-C₈ alkyl, C₃-C₈ cycloalkylor C₆-C₈ aryl radical, can be used. In the supported components theMg/Ti molar ratio is from 0.5:1 to 10:1, in particular from 2:1 to 6:1,and the molar ratio Ti/succinate is from 0.5:1 to 5:1. The inert poroussupport is present in quantities greater than 40% by weight with respectto the total weight of the component. The inert porous support is forexample, porous oxides such as porous metal oxides for example silica,alumina, Al—Si, porous polymer such as styrene/divinylbenzene copolymersdescribed for example in U.S. Pat. No. 5,244,855 or EP 633 272,polyethylene or polypropylene. Preferred inert porous support are metaloxides more preferably silica or alumina. Preferred porous supports havea porosity greater than 0.3 cc/g, measured with the Hg method describedbelow, preferably from 1 to 3 cc/g. The surface area is greater than 30m²/g (BET) and in particular greater than 100 m²/g, more preferably 100to 400 m²/g. The metal oxides generally contain hydroxyl surface groups(e.g. in an amount of from 1 to 5 mmoles/g of oxide), but may also havenone of them. Preferably the oxides are used in the anhydrous state,i.e., free from chemically uncombined water. Chemically uncombinedwater, however, can be present in a quantity smaller than 30 mmoles/g ofsupport. Said water can be removed by subjecting the oxides to heatingat temperatures from 150° C. to 250° C. The amount of hydroxyl groups iscontrolled by calcining the oxides at temperatures usually from 250° C.to 900° C. (the higher the temperature the smaller the number ofhydroxyls present).

Porous polymer are generally free of hydroxy group, but they can also beintroduced in the polymer chain as described for example in EP 633 272,EP 598 543, and U.S. Pat. No. 5,942,586. Different methods can be usedfor the preparation of the catalyst component described in the presentinvention. The preferred method comprises the steps of:

-   (i) in impregnating the inert porous support by suspending it in a    solution of magnesium chloride in an organic solvent, such as    alcohol or ether, or in a hydrocarbon solution (hexane, heptane) of    a MgCl₂.nTi(OR⁷)₄ complex where n is a number from 1 to 3, and R⁷ is    an C₂-C₈ alkyl, C₃-C₈ cycloalkyl or C₆-C₈ aryl radical and then    evaporating the solvent.-   (ii) reacting the support thus obtained with an excess of TiCl₄    containing a succinate of formulal (I) in solution at temperatures    from 60° C. to 135° C.;-   (iii) separating the solid hot from the excess of TiCl₄ and then    washed thoroughly with hexane or heptane until there are no chlorine    ions in the wash.-   (iv) optionally repating the treatments (ii) and (iii).    It is also possible to react the inert porous impregnated of a    magnesium dichloride support first with the succinate of formula (I)    and then with the titanium tetrachloride.

The succinate of formula (I) can also be added during the impregnationof the porous support, or can be reacted after the reaction with thetitanium compound. In this case, it is best to conduct the reaction inthe presence of an aromatic solvent, such as benzene and toluene. Whenthe porous support is used with magnesium compound solutions other thanmagnesium halides, it is best to convert said compounds into halides byreacting them with halogenating agents, such as gaseous HCl, SiCl₄,Al-alkyl halides, and Cl₃SiR⁸ wherein R⁸ has the same meaning than R¹.The support thus impregnated and treated is then reacted with TiCl₄ andwith the ether compound following the methods indicated above.

Suitable magnesium compounds which are other than the magnesium halidesinclude R⁷MgX, MgR⁷ ₂, Mg(OR⁷)₂, XmgOR⁷, MgX₂.nTi(OR⁷)₄ where X is Cl orBr R⁷ is an C₂-C₈ alkyl, C₃-C₈ cycloalkyl or C₆-C₈ aryl radical and n isfrom 1 to 4. In particular, it is an object of the present invention acatalyst for the polymerization of olefins CH₂═CHR, in which R ishydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising theproduct of the reaction between:

-   -   (a) a solid catalyst component comprising an inert porous        support, Mg, Ti and halogen and an electron donor selected from        succinates of formula (I);    -   (b) an alkylaluminum compound and, optionally,    -   (c) one or more electron donor compounds (external donor).

The alkylaluminum compound (b) is preferably selected from the trialkylaluminum compounds such as for example triethylaluminum,triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum,tri-n-octylaluminum. It is also possible to use mixtures oftrialkylaluminum's with alkylaluminum halides, alkylaluminum hydrides oralkylaluminum sesquichlorides such as AlEt₂Cl and Al₂Et₃Cl₃. Alsoalkylalumoxanes can be used.

As mentioned above the catalyst system according to the presentinvention is able to produce a polymer having a polydispersity indexhigher then the corresponding unsupported catalyst.

For applications in which a very high isotactic index is required theuse of an external donor compound is normally advisable. The externaldonor (c) can be of the same type or it can be different from thesuccinate of formula (I). Preferred external electron donor compoundsinclude silicon compounds, ethers, esters, such as ethyl4-ethoxybenzoate, amines, heterocyclic compounds and particularly2,2,6,6-tetramethylpiperidine, ketones and the 1,3-diethers of thegeneral formula (II):

wherein R^(I), R^(II), R^(III), R^(IV), R^(V) and R^(VI) are equal ordifferent to each other, are hydrogen or hydrocarbon radicals havingfrom 1 to 18 carbon atoms, and R^(VII) and R^(VII), equal or differentfrom each other, have the same meaning of R^(I)-R^(VI) except that theycannot be hydrogen; one or more of the R^(I)-R^(VIII) groups can belinked to form a cycle. Particularly preferred are the 1,3-diethers inwhich R^(VII) and R^(VIII) are selected from C₁-C₄ alkyl radicals,R^(III) and R^(IV) form a condensed unsaturated cycle and R^(I), R^(II),R^(V) and R^(VI) are hydrogen. The use of 9,9-bis(methoxymethyl)fluoreneis particularly preferred. Another class of preferred external donorcompounds is that of silicon compounds of formula R_(a) ¹⁰R_(b)¹¹Si(OR¹²)_(c), where a and b are integer from 0 to 2, c is an integerfrom 1 to 3 and the sum (a+b+c) is 4; R¹⁰, R¹¹, and R¹², are C₁-C₁₈hydrocarbon groups optionally containing heteroatoms. Particularlypreferred are the silicon compounds in which a is 1, b is 1, c is 2, atleast one of R¹⁰ and R¹¹ is selected from branched alkyl, alkenyl,alkylene, cycloalkyl or aryl groups with 3-10 carbon atoms optionallycontaining heteroatoms and R¹² is a C₁-C₁₀ alkyl group, in particularmethyl. Examples of such preferred silicon compounds arecyclohexylmethyldimethoxysilane, diphenyldimethoxysilane,methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane,2-ethylpiperidinyl-2-t-butyldimethoxysilane and(1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane and(1,1,1-trifluoro-2-propyl)-methyldimethoxysilane. Moreover, are alsopreferred the silicon compounds in which a is 0, c is 3, R¹¹ is abranched alkyl or cycloalkyl group, optionally containing heteroatoms,and R¹² is methyl. Examples of such preferred silicon compounds arecyclohexyltrimethoxysilane, t-butyltrimethoxysilane andthexyltrimethoxysilane.

The electron donor compound (c) is used in such an amount to give amolar ratio between the organoaluminum compound and said electron donorcompound (c) of from 0.1 to 500, preferably from 1 to 300 and morepreferably from 3 to 100. As previously indicated, when used in the(co)polymerization of olefins, and in particular of propylene, thecatalysts of the invention allow to obtain a broad molecular weighdistribution as indicated by the P.I. values, thus showing an excellentbalance of properties and the processability of the polymers is greatlyimproved. As mentioned above the catalysts of the present invention canbe used in the processes for the polymerization of olefins CH₂═CHR, inwhich R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms.Thus a further object of the present invention is a process forpolymerizing one or more olefins CH₂═CHR, in which R is hydrogen or ahydrocarbyl radical with 1-12 carbon atoms, comprising, to contact underpolymerization condition one or more olefins CH₂═CHR in the presence ofthe catalyst system described above. The preferred α-olefins to be(co)polymerized are ethene, propene, 1-butene, 4-methyl-1-pentene,1-hexene and I-octene. In particular, the above-described catalystsystem can be used in the (co)polymerization of propene and ethylene toprepare different kinds of products.

For example the following products can be prepared: high densityethylene polymers (HDPE, having a density higher than 0.940 g/cm³),comprising ethylene homopolymers and copolymers of ethylene withx-olefins having 3-12 carbon atoms; linear low density polyethylenes(LLDPE, having a density lower than 0.940 g/cm³) and very low densityand ultra low density (VLDPE and ULDPE, having a density lower than0.920 g/cm³, to 0.880 g/cm³) consisting of copolymers of ethylene withone or more α-olefins having from 3 to 12 carbon atoms, having a molecontent of units derived from the ethylene higher than 80%; elastomericcopolymers of ethylene and propylene and elastomeric terpolymers ofethylene and propylene with smaller proportions of a diene having acontent by weight of units derived from the ethylene comprised betweenabout 30 and 70%, isotactic polypropylenes and crystalline copolymers ofpropylene and ethylene and/or other α-olefins having a content of unitsderived from propylene higher than 85% by weight (random copolymers);shock resistant polymers of propylene obtained by sequentialpolymerization of propylene and mixtures of propylene with ethylene,containing up to 30% by weight of ethylene; copolymers of propylene and1-butene having a number of units derived from 1-butene comprisedbetween 10 and 40% by weight. Particularly interesting are the propylenepolymers obtainable with the catalyst of the invention showing broad MWDcoupled with high isotactic index and high modulus. In fact, saidpolymers having a polydispersity index of higher than 4.8, a content ofisotactic units expressed in terms of pentads of higher than 90% and aflexural modulus of at least 1000 MPa. Preferably, the flexural modulusis higher than 1100 and the percent of propylene units in form ofpentads is higher than 95%. Any kind of polymerization process can beused with the catalysts of the invention that are very versatile. Thepolymerization can be carried out for example in slurry using as diluentan inert hydrocarbon solvent, or in bulk using the liquid monomer (forexample propylene) as a reaction medium. Moreover, it is possible tocarry out the polymerization process in gas-phase operating in one ormore fluidized or mechanically agitated bed reactors. The catalystsystem of the present invention can be used as such in thepolymerization process by introducing it directly into the reactor. Inthe alternative, the catalyst system can be pre-polymerized before beingintroduced into the first polymerization reactor. The termpre-polymerized, as used in the art, means a catalyst which has beensubject to a polymerization step at a low conversion degree. Accordingto the present invention a catalyst is considered to be pre-polymerizedwhen the amount the polymer produced is from about 0.1 up to about 1000g per gram of solid catalyst component. The pre-polymerization can becarried out with the α-olefins selected from the same group of olefinsdisclosed before. In particular, it is especially preferredpre-polymerizing ethylene or mixtures thereof with one or more α-olefinsin an amount up to 20% by mole. Preferably, the conversion of thepre-polymerized catalyst component is from about 0.2 g up to about 500 gper gram of solid catalyst component.

The pre-polymerization step can be carried out at temperatures from 0 to80° C. preferably from 5 to 50° C. in liquid or gas-phase. Thepre-polymerization step can be performed in-line as a part of acontinuous polymerization process or separately in a batch process. Thebatch pre-polymerization of the catalyst of the invention with ethylenein order to produce an amount of polymer ranging from 0.5 to 20 g pergram of catalyst component is particularly preferred. The polymerizationis generally carried out at temperature of from 20 to 120° C.,preferably of from 40 to 80° C. When the polymerization is carried outin gas-phase the operating pressure is generally between 0.5 and 10 MPa,preferably between 1 and 5 MPa. In the bulk polymerization the operatingpressure is generally between 1 and 6 MPa preferably between 1.5 and 4MPa. Hydrogen or other compounds capable to act as chain transfer agentscan be used to control the molecular weight of polymer.

The following examples are given in order to better illustrate theinvention without limiting it.

EXAMPLES

Characterization

Determination of X.I.

2.5 g of polymer were dissolved in 250 ml of o-xylene under stirring at135° C. for 30 minutes, then the solution was cooled to 25° C. and after30 minutes the insoluble polymer was filtered. The resulting solutionwas evaporated in nitrogen flow and the residue was dried and weighed todetermine the percentage of soluble polymer and then, by difference, theX.I. %.

Determination of Polydispersity Index (P.I.)

This property is strictly connected with the molecular weightdistribution of the polymer under examination. In particular it isinversely proportional to the creep resistance of the polymer in themolten state. Said resistance called modulus separation at low modulusvalue (500 Pa), was determined at a temperature of 200° C. by using aparallel plates rheometer model RMS-800 marketed by RHEOMETRICS (USA),operating at an oscillation frequency which increases from 0.1 rad/secto 100 rad/sec. From the modulus separation value, one can derive theP.I. by way of the equation:P.I.=54.6*(modulus separation)^(−1.76)in which the modulus separation is defined as:modulus separation=frequency at G′=500 Pa/frequency at G″=500 Pawherein G′ is storage modulus and G″ is the loss modulus.Preparation of the Supports

15 g of silica (Grace 952) having surface area of 300 m2/g and porosity1.55 cm3/g calcinated at 150° C. for 8 hrs were treated with 90 mL of(CH₃)₃SiCl in reflux for 16 hrs. The solid was filtered and washed withanhydrous n-heptane at 60° C. until all traces of (CH₃)₃SiCl wereeliminated, then, the silica was dried under vacuum.

30 g of alumina having surface area of 340 m2/g and porosity 1.78 cm3/g(Ketjen.grade B), calcinated at 150° C. for 6 hrs was used withoutfurther treatments.

Example 1 (Catalyst 1)

5.3 g of silica treated as above were suspended in inert atmosphere in28 mL of anhydrous n-heptane. Then, 24.4 mmoles of MgCl₂ 2.2Ti(OBu)₄,prepared by dissolving a suitable quantity of MgCl₂ in Ti(OBu)₄ at 140°C. for 4 hrs, were added. The mixture was reacted for 4 hrs at 90° C. ina rotavapor flask and then the solvent was evaporated under vacuum. At atemperature of 0° C. in inert atmosphere, 20 g of so obtained Mgmodified silica were slowly added under agitation to 260 mL of TiCl₄containing 3.3 mmoles of diethyl 2,3-bis(isopropyl)succinate. Themixture was heated to 120° C., allowed to react at this temperature for60 min. Then the stirring was discontinued, the solid product wasallowed to settle and the supernatant liquid was siphoned off. 260 mL offresh TiCl₄ were added. The mixture was reacted at 120° C. for 30 min.Then the stirring was discontinued, the solid product was allowed tosettle and the supernatant liquid was siphoned off. Again, 260 mL offresh TiCl₄ were added. The mixture was reacted at 120° C. for 30 min.Then the stirring was discontinued, the solid product was allowed tosettle and the supernatant liquid was siphoned off. The solid was washedsix times with anhydrous hexane (6×100 mL) at 60° C. Finally, the solidwas dried under vacuum. Characterization of the solid is reported intable 1.

Example 2 (Catalyst 2)

5 g silica treated as above are suspended in inert atmosphere in 28 mLof anhydrous n-heptane. Then, 3.5 mmoles of MgCl₂ 2.2Ti(OBu)₄, preparedas described in example 1, were added. The mixture was reacted for 4 hrsat 90° C. in a rotavapor flask and then the solvent was evaporated undervacuum. At a temperature of 0° C. in inert atmosphere, 6 g of the Mgmodified silica were slowly added under agitation to 100 mL of TiCl₄containing 0.45 mmoles of diethyl 2,3-bis(isopropyl)succinate. Themixture was heated to 120° C., allowed to react at this temperature for60 min. Then the stirring was discontinued, the solid product wasallowed to settle and the supernatant liquid was siphoned off. 100 mL offresh TiCl₄ were added. The mixture was reacted at 120° C. for 30 min.Then the stirring was discontinued, the solid product was allowed tosettle and the supernatant liquid was siphoned off. Again, 100 mL offresh TiCl₄ were added. The mixture was reacted at 120° C. for 30 min.Then the stirring was discontinued, the solid product was allowed tosettle and the supernatant liquid was siphoned off.

The solid was washed six times with anhydrous hexane (6×100 mL) at 60°C. Finally, the solid was dried under vacuum. The resulting solid wassampled for the characterization the results are reported in table 1.

Example 3 (Catalyst 3)

5.3 g of alumina are suspended in inert atmosphere in 28 mL of anhydrousn-heptane. Then, 24.4 mmoles of MgCl₂ 2.2Ti(OBu)₄, prepared as describedin example 1, were added. The mixture was reacted for 4 hrs at 90° C. ina rotavapor flask and then, the solvent was evaporated under vacuum. 20g of the so obtained solid were reacted with TiCl₄ according to theprocedure of example 1, washed and dried.

Characterization of the solid so obtained is reported in table 1.

Example 4 (Catalyst 4)

6.2 g of alumina are suspended in inert atmosphere in 45 mL of anhydrousethanol containing 26 mmoles of MgCl₂. The mixture was reacted for 4 hrsat 70° C. in a rotavapor flask and then, the ethanol was evaporateduntil a residual ethanol content of 4.9 moles of EtOH per mole of MgCl₂was obtained. 6 g. of the so obtained solid were reacted with TiCl₄according to the procedure of example 1 but using 1.8 mmoles of, diethyl2,3-bis(isopropyl)succinate.

Characterization of the solid so obtained is reported in table 1.

Example 5 (Catalyst 5)

6.2 g of alumina are suspended in inert atmosphere in 25 mL of anhydroustetrahydrofurane containing 25 mmoles of n-ButylMgCl. The mixture wasreacted for 4 hrs at 30° C. in a rotavapor flask and then, the solventwas evaporated.

The solid was suspended in 12.5 mL of fresh tetrahydrofurane and, then,a solution of 25.mmoles of ethanol (EtOH) in 12.5 mL of tetrahydrofuranewas slowly added dropwise at a temperature of 0° C. The mixture wasreacted for 4 hrs at room temperature in a rotavapor flask and then, thesolvent was evaporated.

5 g. of the so obtained solid were reacted with TiCl₄ according to theprocedure of example 1 but using 2.4 mmoles of, diethyl2,3-bis(isopropyl)succinate. Characterization of the solid so obtainedis reported in table 1.

Example 6 (Catalyst 6)

12 g of silica not treated as described above were suspended, at roomtemperature and in inert atmosphere, in 120 mL of anhydrous heptane.Then, a solution containing 100 mmoles of Mg(n-Butyl)₂ in n-heptane wasadded dropwise under agitation. The temperature was rised to 90° C. andmantained for 1 h. The suspension was cooled down at a temperature of20° C. and gaseous HCl was passed in it in 180 min, at constant stirringand mantaining the said temperature. The molar ratio between HCl and theorganomagnesium compound was 10. After 30 min of post reaction, theliquid was filtered off and the solid was washed with anhydrous hexane.The solid was suspended in 120 mL of anhydrous heptane and, at 25° C.under stirring, 296 mmoles of anhydrous ethanol were added. Thetemperature was rised to 80° C. and mantained for 90 minutes understirring, then, the suspension was cooled to 25° C. and 600 mmoles ofTiCl₄ and 16.7 mmoles of diethyl 2,3-bis(isopropyl)succinate were added.The temperature was rised to 100° C. and kept for 120 minutes understirring. Then the stirring was discontinued, the solid product wasallowed to settle and the supernatant liquid was siphoned off. 320 mL ofanhydrous toluene and mL 26 of TiCl₄ were added. The mixture was reactedat 110° C. for 120 minutes. Then the stirring was discontinued, thesolid product was allowed to settle and the supernatant liquid wassiphoned off. The solid was washed once with anhydrous toluene (1×100mL) at 110° C., then, six times with anhydrous hexane(6×100 mL) at 60°C. Finally, the solid was dried under vacuum. Characterization of thesolid is reported in table 1.

Comparative Example 1 (Catalyst 7)

At a temperature of −20° C. and in inert atmosphere, 100 mmoles of MgCl₂2.2Ti(Obu)₄, prepared as described in example 1, were added to 350 mL ofanhydrous toluene containing 16.7 mmoles of diethyl2,3-bis(isopropyl)succinate. At this temperature, 350 mL of TiCl₄ wereadded dropwise in 120 minutes under stirring. The mixture was heated andreacted at a temperature of 100° C. for 60 minutes and, then, filteredat 100° C. The solid was washed once with anhydrous toluene (1×100 mL)at 110° C., then, six times with anhydrous hexane(6×100 mL) at 60° C.Finally, the solid was dried under vacuum. Characterization of the solidis reported in table 1.

Propylene Polymerization: General Procedure

In a 4 liter autoclave, purged with nitrogen flow at 70° C. for onehour, 75 ml of anhydrous hexane containing 800 mg of AlEt₃, 79.8 mg ofdicyclopentyldimethoxysilane and 10 mg of solid catalyst componentindicated in table 2 were introduced in propylene flow at 30° C. Theautoclave was closed. 1.5 Nl of hydrogen were added and then, understirring, 1.2 Kg of liquid propylene were fed. The temperature wasraised to 70° C. in five minutes and the polymerization was carried outat this temperature for two hours. The autoclave was vented and therecovered polymer was dried at 70° C. under vacuum for three hours. Thefeatures of the obtained polymers are reported in table 2 TABLE 1 Mg Tidiethyl 2,3-bis(isopropyl)- Examples wt % wt % succinate wt % 1 2.8 1.82.7 2 1 0.9 1.1 3 4 2.9 4.7 4 7.4 2.7 6.2 5 6.1 2.5 4.9 6 6.3 4.6 6.3Comp 1 15.7 4.9 12

TABLE 2 polymerization X.I. MFR Example Catalyst Wt % g/10′ P.I. 1 198.6 0.5 5.0 2 2 98.8 1.2 6.8 3 3 98.5 0.3 5.0 4 4 98.3 0.3 5.0 5 5 98.40.8 6.0 6 6 98.2 0.8 5.3 Comp 1 7 98.6 0.8 4.5

1. A solid catalyst component for the polymerization of olefins offormula CH₂═CHR, in which R is hydrogen or a hydrocarbyl radical with1-12 carbon atoms, comprising: an inert porous support, Mg, Ti, halogenand an electron donor selected from succinates of formula (I):

wherein the radicals R¹ and R², equal to or different from each other,are a linear or branched, saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀cycloalkyl, C₆-C₂₀ aryl, C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical,optionally containing heteroatoms belonging to groups 13-17 of theperiodic table of the elements; the radicals R³, R⁴, R⁵ and R⁶, equal toor different from each other, are hydrogen or a linear or branched,saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀ cycloalkyl, C₆-C₂₀ aryl,C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical, optionally containingheteroatoms belonging to groups 13-17 of the periodic table of theelements; and the radicals R³, R⁴, R⁵ and R⁶ which are joined to thesame carbon atom can be linked together to form a C₃-C₈ ring.
 2. Thesolid catalyst component according to claim 1 comprising a titaniumcompound, having at least a Ti-halogen bond, the compound of formula(I), and a Mg halide which are supported on an inert porous support. 3.The solid catalyst component according to claim 1 in which the electrondonor compound of formula (I) is selected from those in which R₁ and R₂are C₁-C₈ alkyl, cycloalkyl, aryl, arylalkyl and alkylaryl groups. 4.The solid catalyst component according to claim 3 in which R₁ and R₂ areselected from primary alkyls.
 5. The solid catalyst component accordingto claim 1 in which the electron donor compound of formula (I) isselected from those in which R₃ to R₅ are hydrogen and R₆ is a branchedalkyl, cycloalkyl, aryl, arylalkyl and alkylaryl radical having from 3to 10 carbon atoms.
 6. The solid catalyst component according to claim 5in which R₆ is a branched primary alkyl group or a cycloalkyl grouphaving from 3 to 10 carbon atoms.
 7. The solid catalyst componentaccording to claim 1 in which the electron donor compound of formula (I)is selected from those in which at least two radicals from R₃ to R₆ aredifferent from hydrogen and are selected from C₁-C₂₀ linear or branchedalkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl groupsoptionally containing heteroatoms.
 8. The solid catalyst componentaccording to claim 7 in which the two radicals different from hydrogenare linked to the same carbon atom.
 9. The solid catalyst componentaccording to claim 7 in which the two radicals different from hydrogenare linked to different carbon atoms.
 10. The solid catalyst componentaccording to claim 9 in which the succinate of formula (I) is selectedfrom diethyl 2,3-diisopropylsuccinate, diisobutyl2,3-diisopropylsuccinate, di-n-butyl 2,3-diisopropylsuccinate, diethyl2,3-dicyclohexyl-2-methylsuccinate, diisobutyl2,3-dicyclohexyl-2-methylsuccinate, diisobutyl 2,2-dimethylsuccinate,diethyl 2,2-dimethylsuccinate, diethyl 2-ethyl-2-methylsuccinate,diisobutyl 2-ethyl-2-methylsuccinate, diethyl2-(cyclohexylmethyl)-3-ethyl-3-methylsuccinate, and diisobutyl2-(cyclohexylmethyl)-3-ethyl-3-methylsuccinate.
 11. The solid catalystcomponent according to claim 1 wherein the inert porous support is aporous metal oxide, or a porous polymer.
 12. The solid catalystcomponent according to claim 11 wherein the inert porous support is aporous metal oxide.
 13. The solid catalyst component according to claim12 wherein the inert porous support is silica or alumina.
 14. The solidcatalyst component according to claim 1 wherein the inert porous supporthas a porosity greater than 0.3 cc/g, measured with the Hg method. 15.The solid catalyst component according to claim 1 wherein the surfacearea of the inert porous support is greater than 30 m²/g (BET).
 16. Aprocess for preparing a solid catalyst component comprising an inertporous support, Mg, Ti, halogen and an electron donor selected fromsuccinates of formula (I):

wherein the radicals R¹ and R², equal to or different from each other,are a linear or branched, saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀cycloalkyl, C₆-C₂₀ aryl, C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical,optionally containing heteroatoms belonging to groups 13-17 of thePeriodic Table of the Elements; the radicals R³, R⁴, R⁵ and R⁶, equal toor different from each other, are hydrogen or a linear or branched,saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀ cycloalkyl, C₆-C₂₀ aryl,C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical, optionally containingheteroatoms belonging to groups 13-17 of the Periodic Table of theElements; and the radicals R³, R⁴, R⁵ and R⁶ which are joined to thesame carbon atom can be linked together to form a C₃-C₈ ring, theprocess comprising the steps of: (i) impregnating an inert poroussupport by suspending it in a solution of magnesium chloride in anorganic solvent, such as alcohol or ether, or in a hydrocarbon solution(hexane, heptane) of a MgCl₂.nTi(OR⁷)₄ complex where n is a number from1 to 3, and R⁷ is an C₂-C₈ alkyl, C₃-C₈ cycloalkyl or C₆-C₈ aryl radicaland then evaporating the solvent. (ii) reacting the support obtainedfrom step (i) with an excess of TiCl₄ containing a succinate of formulal(I) in solution at temperatures from 60° C. to 135° C.; (iii) separatingthe hot solids from the excess of TiCl₄ and then washing thoroughly withhexane or heptane until there are no chlorine ions in the wash; and (iv)optionally repeating the treatments (ii) and (iii).
 17. A catalyst forthe polymerization of olefins CH₂═CHR, in which R is hydrogen or ahydrocarbyl radical with 1-12 carbon atoms, comprising the product ofthe reaction between: (a) a solid catalyst component comprising an inertporous support, Mg, Ti and halogen and an electron donor selected fromsuccinates of formula (I)

wherein the radicals R¹ and R², equal to or different from each other,are a linear or branched saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀cycloalkyl, C₆-C₂₀ aryl, C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical,optionally containing heteroatoms belonging to groups 13-17 of thePeriodic Table of the Elements; the radicals R³, R⁴, R⁵ and R⁶, equal toor different from each other, are hydrogen or a linear or branchedsaturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀ cycloalkyl, C₆-C₂₀ aryl,C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical, optionally containingheteroatoms belonging to groups 13-17 of the Periodic Table of theElements: and the radicals R³, R⁴, R⁵ and R⁶ which are joined to thesame carbon atom can be linked together to form a C₃-C₈ ring; (b) analkylaluminum compound and, optionally, (c) at least one electron donorcompounds (external donor).
 18. A process for polymerizing one or moreolefins CH₂═CHR, in which R is hydrogen or a hydrocarbyl radical with1-12 carbon atoms, comprising, contacting under polymerization conditionone or more olefins CH₂═CHR in the presence of a catalyst comprising theproduct of the reaction between: (a) a solid catalyst componentcomprising an inert porous support, Mg, Ti and halogen and an electrondonor selected from succinates of formula (I):

wherein the radicals R¹ and R², equal to or different from each other,are a linear or branched, saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀cycloalkyl, C₆-C₂₀ aryl, C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical,optionally containing heteroatoms belonging to groups 13-17 of thePeriodic Table of the Elements; the radicals R³, R⁴, R⁵ and R⁶, equal toor different from each other, are hydrogen or a linear or branched,saturated or unsaturated C₁-C₂₀ alkyl, C₃-C₂₀ cycloalkyl, C₆-C₂₀ aryl,C₇-C₂₀ alkylaryl or C₇-C₂₀ arylalkyl radical, optionally containingheteroatoms belonging to groups 13-17 of the Periodic Table of theElements; and the radicals R³, R⁴, R⁵ and R⁶ which are joined to thesame carbon atom can be linked together to form a C₃-C₈ ring; (b) analkylaluminum compound and, optionally, (c) at least one electron donorcompounds (external donor).